Banks Finished the ISO 20022 Switch. The Harder Work Starts Now.

On 22 November 2025, Swift ended the coexistence period between its old MT message formats and ISO 20022 for cross-border payments. The industry agreed to adopt the standard back in 2018, and the coexistence window itself had been open since March 2023. Just before Swift announced the switch was complete, it saw 97% of payment instructions on its network being sent in ISO 20022.

So the migration is done. Or is it?

Sending a message in a new format is one job. Using the data inside it is another, and on that second job a lot of banks are still near the starting line.

Why the Richer Data Matters

The old MT messages were designed around tight field limits and free text. Names, addresses and remittance details were often squeezed into a few lines, with little agreement on what went where. ISO 20022 replaces that with structured fields. An address can be split into street, town and country. The purpose of a payment can carry a code. Remittance information can hold far more detail than before.

When the switch was completed, Swift's chief operations officer Jerome Piens called this structured data "foundational to the future of payments". That is a fair description. Better-structured data should mean fewer false positives in sanctions screening and fewer payments stuck in manual repair queues. It should also mean easier reconciliation for corporate clients who want to match incoming money against invoices.

But none of that happens by itself.

Where the Value Gets Lost

Many banks met the deadline by putting a translation layer in front of their existing systems. Messages arrive in ISO 20022, get converted into whatever format the core payments engine, the screening tool or the data warehouse already understands, and carry on from there. It was a sensible way to hit a hard date. It also means the richer data can be squeezed back into old field structures before anyone downstream gets to use it.

Swift itself offered a contingency service to convert remaining MT instructions into ISO 20022 after the cutover. That tells you how uneven readiness was across the network.

The result is a bank that speaks the new language at the edge and the old one everywhere else. Screening teams still look at truncated name fields. Analysts still can't query purpose codes because the warehouse never stored them. And the business case that justified years of migration work stays mostly on paper.

What Fixing It Involves

Most of the remaining work sits in the data layer rather than the messaging layer.

It starts with keeping the full message. Store the ISO 20022 payload in its structured form alongside whatever legacy record the core system needs, so nothing is thrown away at the point of entry. From there, teams can build pipelines that send specific fields to the systems that need them. Structured addresses go to screening, purpose codes go to analytics, and remittance details go to reconciliation.

Data quality checks belong at that same entry point. Counterparties will keep sending incomplete or badly populated messages for some time. It helps to know which correspondents do this before their payments land in a repair queue.

Banks without the in-house capacity often bring in specialist data engineering services for this groundwork. The tricky part is designing data models and pipelines that will still hold up as more domestic payment schemes adopt the same standard.

Does every system need rebuilding at once? No. A more practical route is to pick one use case with a cost you can measure, such as manual repairs or screening false positives, and work out which ISO 20022 fields would bring it down. Then make sure those fields survive all the way to the system that needs them.

The Deadline Was Only the Start

Swift's network links more than 11,500 institutions and corporates in over 200 countries and territories, and all of them now exchange payment instructions in the same structured standard. The banks that get the most out of it will be the ones that saw 22 November 2025 as the day their payment data finally became usable. Then they went and used it.

Author - Shefali Vasave

Shefali manages content marketing at Opus Technologies, a domain-native engineering partner for banks, payment providers, and fintechs, and writes on the various aspects of financial institutions navigating change in a real-time, digital-first world.